YZ Engineering Guide
Form: 161.01-EG1 (0618)
11
The graphic display also allows information to be represented in both SI and Imperial units of measure, and has the
ability to display many languages.
OptiView
™ continually monitors the system operation and records the cause of any shutdowns (safety, cycling or
normal). This information is recorded in memory and is preserved even through a power failure condition, so the user
may recall it for viewing at any time. During operation, the user is continually advised of the operating conditions by
various status and warning messages. By providing a common networking protocol through the Building Automation
System (BAS), YORK® chillers not only work well individually, but also as a part of the building system. This networking
protocol allows increased remote control of the chiller, as well as 24-hour performance monitoring via a remote site. In
addition, compatibility is maintained with the present network of BAS communications. Both of these remote control
capabilities allow for the standard Energy Management System (EMS) interface:
1. Remote Start
2. Remote Stop
3. Remote leaving chilled liquid temperature setpoint adjustment
4. Remote current limit setpoint adjustment
5. Pulse Width Modulation
6. Remote
“Ready to Start” Contacts
7. Safety Shutdown Contacts
8. Cycling Shutdown Contacts
HEAT EXCHANGERS
Shells
Evaporator and condenser shells are fabricated from rolled carbon steel plates with fusion welded seams or carbon steel
pipe. Carbon steel tube sheets, drilled and reamed to accommodate the tubes, are welded to the end of each shell.
Intermediate tube supports are fabricated from carbon steel plates, and drilled and reamed to eliminate sharp edges.
The refrigerant side of each shell is designed, tested, and stamped in accordance with local pressure vessel codes.
Tubes
Heat exchanger tubes are copper alloy high-efficiency, externally and internally enhanced to provide optimum
performance. Utilizing the
“skip-fin” tube design provides a smooth internal and external surface at each intermediate
tube support. This provides extra wall thickness (up to twice as thick) and non work-hardened copper at the support
location, extending the life of the heat exchangers. Each tube is expanded into the tube sheets providing a leak-proof
seal, and is individually replaceable.
Evaporator
The evaporator is a patented hybrid falling-film type heat exchanger. It contains a balance of flooded and falling-film
technology to optimize efficiency, minimize refrigerant charge, and maintain reliable control. A specifically designed spray
header provides uniform distribution of refrigerant over the entire shell length to yield optimum heat transfer. A suction
eliminator is located above the tube bundle to prevent liquid refrigerant carryover into the compressor. A 38 mm (1.5")
liquid level sight glass is conveniently located on the side of the shell to aid in determining proper refrigerant charge. The
evaporator shell contains a dual refrigerant relief valve arrangement or a single relief valve arrangement if the chiller is
supplied with the optional refrigerant isolation valves. A 25.4 mm (1") refrigerant charging valve is provided for service
access.